Classifications

• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/02—Treatment of water, waste water, or sewage by heating
  • C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
  • C02F1/10—Treatment of water, waste water, or sewage by heating by distillation or evaporation by direct contact with a particulate solid or with a fluid, as a heat transfer medium
  • C02F1/12—Spray evaporation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D1/00—Evaporating
  • B01D1/0011—Heating features
  • B01D1/0017—Use of electrical or wave energy
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D5/00—Condensation of vapours; Recovering volatile solvents by condensation
  • B01D5/0057—Condensation of vapours; Recovering volatile solvents by condensation in combination with other processes
  • B01D5/006—Condensation of vapours; Recovering volatile solvents by condensation in combination with other processes with evaporation or distillation
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/48—Treatment of water, waste water, or sewage with magnetic or electric fields
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S159/00—Concentrating evaporators
  • Y10S159/01—Electric heat
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S159/00—Concentrating evaporators
  • Y10S159/26—Electric field
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S203/00—Distillation: processes, separatory
  • Y10S203/11—Batch distillation

Definitions

• the present invention relates to a method for purifying a liquid comprising liquid particles and residual particles. It is hereby possible to generate substantially pure water from for instance seawater.
• a known system for desalinating seawater, and thereby converting it into fresh water, is membrane distillation. Here salt water is heated, wherein the water evaporates and passes through a membrane, after which the water vapour condenses on a relatively cool condensation surface and relinquishes the heat to the salt water to be heated. The condensation is then discharged as substantially pure fresh water.
• membranes are a costly aspect of the whole purification process. Not only are the membranes expensive to produce and purchase, the membranes are also susceptible to contamination, whereby they begin to operate less efficiently. An additional problem is that many membranes are essentially sensitive to temperature and, particularly at higher temperatures, become less efficient in use. The evaporation of the liquid further requires a great deal of energy.
• the present invention has for its object to provide a method for purifying a liquid, wherein the purification is performed in a more efficient manner.
• the present invention provides a method for purifying a liquid comprising liquid particles and residual particles, comprising the steps of: heating the liquid with liquid particles and residual particles for purifying; - carrying the liquid in the form of liquid droplets into a purification space; applying a similar electric charge to the liquid droplets and to a condensation surface; - evaporating liquid particles in the purification space; - condensing the evaporated liquid particles on the condensation surface; discharging the condensation and the unevaporated residual particles separately.
• Liquid can evaporate efficiently by heating the liquid for purifying and distributing or vapourizing this heated liquid in a purification space. Applying electric charge to the liquid droplets achieves that the droplets become unstable. Once the critical point has been passed, these droplets are then distributed as a type of mist of charged particles. These particles have a diameter in the order of magnitude of 10 ⁇ m or even smaller. The process (“Electro-Spraying") of vapourizing the particles can also be repeated. Liquid evaporates from the particles. An efficient evaporation process is hereby obtained. The evaporated liquid will then seek a surface on which to condense.
• the condensation surface will here have a lower temperature than the particles.
• a substantially pure liquid flow is obtained by then collecting the condensation and discharging it separately.
• the unevaporated residual particles are discharged as a residual flow.
• the applying of said charge has the result, among others, that no membrane is required to separate the evaporated liquid particles from the residual particles.
• An advantageous process is hereby obtained, the operation of which is not diminished through use as a result of for instance contamination.
• the liquid is seawater which is purified into fresh water suitable for consumption.
• the evaporated liquid particles are guided to the condensation wall.
• the liquid particles By guiding the liquid particles to the condensation wall a greater part of the liquid for purifying is separated from the residual particles. This guiding can take place by making use of an extra gas flow and/or a pressure difference. A greater output can hereby be realized from the process.
• An additional advantage is that the residual flow will comprise fewer liquid particles and will therefore be smaller, with for instance a higher concentration of salt.
• the step of heating a liquid comprises of carrying the liquid though a heat exchanger and further heating the liquid with an external source.
• Owing to the use of a heat exchanger to heat the liquid use can be made of the energy released from, among others, the condensation process and/or the remainder of the residual flow.
• An external energy source is necessary for the purpose of supplying extra energy in order to maintain the process .
• this energy source is embodied as an additional heat exchanger.
• Energy in the form of heat can be supplied to the liquid in relatively simple manner by using a heat exchanger.
• the heat exchanger can for instance obtain this heat in the form of a residual energy originating from another process preferably located nearby.
• Use can herein also be made for instance of solar energy.
• the heating of the liquid preferably takes place in counter-flow to the evaporation, condensation and/or discharge.
• the use of the energy required for the process is hereby managed most efficiently.
• a positive charge is further preferably applied to both the liquid droplets and the condensation surface. The most efficient use is hereby made of properties of the substances involved.
• the residual particles are repelled by the condensation surface and attracted by a discharge wall to which a charge opposite to that on the condensation wall is applied.
• the direction of the flow of residual particles can further be directed by the use of a discharge wall to which a charge opposite to that on the condensation wall is applied.
• the residual particles are hereby attracted and the purification of the liquid is further improved.
• the charge can be applied by making use of one or more power sources.
• the discharge wall can for instance also be provided with a charge by an process of induction.
• the residual flow is used for energy generation by making use of the pressure difference between salt and fresh water.
• a membrane potential is set by for instance making use of an ion-selective membrane which separates salt water from fresh water. This potential amounts to about 80 mV.
• the small voltage difference can optionally be increased by placing a plurality of compartments in series in order to use a greater voltage difference, whereby electricity can be generated.
• a relatively high voltage difference can be realized using a membrane, whereby electricity can be generated in more efficient manner by making use of this residual flow.
• the present invention further also relates to a device for purifying a liquid.
• the device provides the same effects and advantages as those stated with reference to the method.
• a double-walled cylinder is provided as heat exchanger and condensation surface.
• the incoming liquid flow can for instance be heated by the outer edge, after which evaporation, condensation and discharge of the separated flows takes place through the centre of the cylinder.
• the incoming liquid flow can of course also be guided through the centre of the cylinder and the discharge through the outer edge.
• An advantageous device can be realized in efficient manner with such a double-walled cylinder.
• the liquid for purifying is heated to about 200 0 C in order to intensify the evaporation step.
• the heat content of the liquid flow is increased.
• a greater part of the water will hereby evaporate in the evaporation step.
• the optimum temperature depends on the specific process conditions, such as magnitude of flow rates, heat-exchanging surfaces and so on.
• the temperature of the liquid for purifying will preferably be brought above 100 0 C, to about 125 0 C, more preferably to about 150 0 C, and most preferably to 200 0 C or even higher. It will be apparent that, when the temperatures are too high, among other things the heat loss will become so great that the process will progress less efficiently.
• Figure 1 shows a schematic view of a known principle for purifying liquid
• Figure 2 shows a schematic view of the method according to the invention
• Figure 3 shows a schematic view of an embodiment according to the diagram of figure 2.
• FIG 4 shows an alternative embodiment, connected in parallel, of the purification according to the invention.
• a device 2 for purifying a liquid (figure 1) takes up a salt flow 4, such as seawater.
• a salt flow 4 comprises about 35 g of salt per litre of salt water.
• this salt water has a temperature of for instance 25°C.
• a non-porous tube 6 the liquid is heated to a temperature of about 80 0 C of the outgoing flow 8.
• This flow 8 is further heated by a heating element 10, and this results in an extra-heated flow of about 95 0 C.
• the extra-heated flow 12 then enters a porous tube 14.
• Device 26 takes up and carries salt water 28 through tube 30.
• the water flow is herein heated from about 25 0 C of ingoing flow 28 to about 80 0 C of outgoing flow 32.
• This flow 32 is then further heated by heating element 34 to form extra-heated flow 36.
• This extra-heated flow 36 has a temperature of about 95 0 C.
• Flow 36 is carried to a sprayer or vaporizer 38.
• Sprayer 38 is provided with a needle-shaped outflow (not shown) .
• the sprayer is connected to a charge source 40 via connection 42.
• Charge source 40 provides the liquid in the sprayer with a charge by applying an electric voltage.
• Flow 36 is then distributed over droplet flows 44 by sprayer 38. Water from these droplets can evaporate and is carried by fan 47 in the direction of condensation surface 48 as water vapour flow 46.
• Condensation surface 48 is provided with the same charge as sprayer 38 by the charge source 50 by means of connection 52. Only the flow of water vapour 46 will condense onto condensation surface 48 and the residual particles will be discharged as residual flow 54.
• the residual particles are attracted by a plate 56, which is provided with a charge by source 58 by means of connection 60.
• the charge on plate 56 is opposite to the charge of condensation wall 48. Alternatively, the charge on plate 56 can be obtained by induction.
• Flow 44 can be directed by making use of a fan 49. Use can here be made of air or another gas .
• a device 62 for purifying a liquid (figure 3) , as according to the operation shown in figure 2, is formed by a double-walled cylinder 64.
• This cylinder 64 has an outer wall 66 and an inner wall 68.
• An ingoing flow 70 formed by seawater flows through a passage 72 formed by outer wall 66 and inner wall 68.
• Outgoing flow 74 is further heated by a heating element 76, resulting in an extra-heated flow 78.
• Hot flow 78 is carried to sprayer 80, which distributes flow 78 as a droplet flow 82. Water can evaporate from this flow 82 and forms a flow of water vapour 84 which will condense on the relatively cold inner wall 68. The condensation is collected and carried further as pure water flow 86.
• Sprayer 80 is connected to charge source 90 via connection 92.
• Inner wall 68 is connected to voltage source 94 via connection 96.
• Residual flow 88 is collected by collecting wall 98, which is connected to a power source 100 via connection 102.
• the ingoing flow is heated from a temperature of 25°C to about 8O 0 C at outgoing flow 74. Due to the additional heating the extra-heated flow 78 has a temperature of about 95°.
• the heating from 25°C to 80 0 C can be achieved by making use of the released condensation heat and the cooling of the flows on the inner side of the double-walled cylinder.
• Flows 86 and 88 cool from 95°C close to sprayer 80 to about 28°C when leaving device 62.
• Power sources 90 and 94 apply the same charge to sprayer 80 and inner wall 68, wherein inner wall 68 functions as condensation surface.
• Discharge wall 98 is on the other hand provided with an opposite charge by power source 100. The residual particles are hereby attracted by this wall and will not deposit against condensation wall 68.
• Pure separation of residual flow 88 and pure water flow 86 can hereby be realized. Flows can optionally be forced by fans and/or for instance pressure differences.
• the device 104 (figure 4) is provided with a number of plates 106. An ingoing flow 108 is carried alternately between these plates or tubes/cylinders 106. This flow is heated by the released condensation heat in the purification spaces provided between ingoing flows 108.
• Ingoing flow 108 is carried to sprayer 116 by means of conduits 110, via one or more heating elements 112 and conduits 114.
• This sprayer 116 is provided with charge from a charge source 118 via connection 120.
• the sprayers can herein be provided with charge from one charge source 118 or each be provided with their own source.
• the vapourized flow 122 is directed by a fan 124. Liquid will evaporate and come to lie in a flow 126 on plates 106, where condensation takes place on the relatively cold surface. Plates 106 are provided with charge from energy source 128 via connection 130. The condensation is discharged with condensation flow 132. Residual flow 134 comes to lie on plate 136, which is provided with a charge from energy source 138 via connection 140.
• the further operating principle is the same as that in the above discussed embodiments.
• the present invention is in no way limited to the above described preferred embodiment; the rights sought are defined by the following claims, within the scope of which many modifications can be envisaged. It is thus possible for instance to combine the power sources into one source, such as power sources 90 and 94 of figure 3. It is further possible to make use of the earth' s electric field, for instance by bringing sprayer 80 to the voltage of higher air layers. In order to apply a voltage use can for instance also be made of a Kelvin pot, wherein falling water droplets are used to generate voltage differences, making use of electrostatic induction which occurs between two mutually connected and oppositely charged sub-systems. Although the charge can be applied to the liquid droplets in sprayer 38, it is for instance also possible to envisage applying the charge to the vapourized flow.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Hydrology & Water Resources (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Heat Treatment Of Water, Waste Water Or Sewage (AREA)
• Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
• Degasification And Air Bubble Elimination (AREA)
• Separation Using Semi-Permeable Membranes (AREA)

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• 2007
  • 2007-01-18 NL NL1033253A patent/NL1033253C2/nl not_active IP Right Cessation
• 2008
  • 2008-01-16 US US12/448,926 patent/US8974643B2/en not_active Expired - Fee Related
  • 2008-01-16 ES ES200990012A patent/ES2350343B8/es not_active Expired - Fee Related
  • 2008-01-16 WO PCT/NL2008/000013 patent/WO2008088211A2/en active Application Filing
  • 2008-01-16 CN CN200880002570.7A patent/CN101641293B/zh not_active Expired - Fee Related

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